After clicking on Edit, Don't see "custom thumbnail", just the three defaulted ones they picked.

Oh, sorry. You have to be a YT partner, or have a monetized channel, and have no copyright strikes. My bad.
If you've just created it... give it some weeks/months and keep the acct. in good standing and you will eventually get it.

Sorry to jump in here, I just want to make light of a simpler way to adjust trim step. The problem with doing it that way is exactly what you said, you will have to retrim your plane. The purpose of trims steps was to allow you to get your trims "close" by having a higher step and therefor you wouldn't have to click the trim as much while flying. Then you can adjust the trim step down to fine tune it without loosing your current trim setting.

Go into the linkage menu and go to the second page. Then scroll down to T1-T4 SET. Then drop the step on T1, T2, and T4 down to 1. (Default is 4). T3 is throttle so no reason to adjust the trim step on that.

Nice, that's even better. I had been re-centering my trims to 0 using subtrim and then dropping the trim rate down to get it finer, but this would be less work.

Oh, sorry. You have to be a YT partner, or have a monetized channel, and have no copyright strikes. My bad.
If you've just created it... give it some weeks/months and keep the acct. in good standing and you will eventually get it.

Sorry to jump in here, I just want to make light of a simpler way to adjust trim step. The problem with doing it that way is exactly what you said, you will have to retrim your plane. The purpose of trims steps was to allow you to get your trims "close" by having a higher step and therefor you wouldn't have to click the trim as much while flying. Then you can adjust the trim step down to fine tune it without loosing your current trim setting.

Go into the linkage menu and go to the second page. Then scroll down to T1-T4 SET. Then drop the step on T1, T2, and T4 down to 1. (Default is 4). T3 is throttle so no reason to adjust the trim step on that.